In production engineering, for example, among other things, for safety reasons, machines and systems are set up within a space separated from the exterior and in which a person is not permitted to remain during operation of the machine. For example, to have access to the machine for maintenance work, the space-separating device generally has a closable opening. Generally speaking, operation of the machine should only be possible when the opening is closed, and the closed state is locked. Access to the machine is only possible when the locking of the closed state is neutralized.
DE 203 15 959 U1 discloses a device for monitoring the state of a space-separating device, in which it is ensured that a person located within the separated space is not able to close the space-separating device and lock it from the inside. Otherwise, there would be the risk that the machine could start inadvertently or intentionally while a person is located within the space-separating device.
DE 196 32 962 A1 discloses a door actuation device. From the interior of the space-separating device, a latch locking the closed state can be transferred into its unlocking position. The space-separating device can then be opened. Conversely, the latch cannot be transferred into its locking position, this movement possible only from the outside. In this way a type of “escape unlocking” is implemented.
DE 10 2005 057 108 A1, published at a later date, discloses a safety switch for producing a release signal depending on the position of a movable protective door. The part to be attached to the protective door has an actuator movable between a first position and a second position. The part to be attached to the frame has a recess engagable by the actuator in the second position. A blocking element can block the actuator in the second position.
DE 298 24 200 U1 discloses a device enabling an individual inadvertently locked within the protective enclosure to leave this protective enclosure. At the same time, the machines located within the protective enclosure can only be operated when the door on which the device is located is not only closed, but locked.